Control mechanism for type bars including a pivotable rake



April 11, 1967 o. AEBI 3,313,388

CONTROL MECHANISM FOR TYPE BARS INCLUDING A PIVOTABLE RAKE Filed Oct. 7,1965 2 Sheet's Sheet 1 INVENTOR ATTORNEY Aprifl 11, 1967 o. AEBI CONTROLMECHANISM FOR TYPE BARS INCLUDING A PIVOTABLE RAKE 2 Sheets-Sheet 2?Filed Oct.

INVENTOR A ORNEY United States Patent 3,313,333 CONTROL MECHANISM FORTYPE BARS INCLUDING A PIVOTABLE RAKE Otto Aebi, Yverdon, Switzerland,assignor to Paiilard S.A., Vaud, Switzerland, a corporation ofSwitzerland Filed Oct. 7, 1965, Ser. No. 493,833 Claims priority,application Switzerland, June 2, 1965, 7,708/65 3 Claims. (Cl. 197-74)The present invention relates to a control mechanism for the type barsof a typewriter. The type bars are pivoted on a basket which may beremoved by the operation of a motion lever to change from typing inlower case type to typing in upper case type. The type bars are eachcontrolled from a key lever by means of a lever pivoted on a movablerake, one end of this lever being connected to the key lever by adraw-rod, the other end of this lever being connected to the type bar bya second draw-rod. The movement of the rake is controlled by theoperation of a motion lever, so as to substantially to preserve the samerelative disposition between the different connecting members betweenthe key lever and the type bar for the striking of lower case and uppercase type.

For such mechanisms, one always searches for the most simple means forestablishing the kinematics involved. The movement imparted to the keylever must be transmitted to the type bar by a minimum of elements,which are simple to manufacture and are of low inertia. Numeroussolutions are known which satisfy, more or less, these criteria.

The problem is rendered more intricate by the fact that, on the onehand, the movement of the key levers which pivot about a horizontal axismust be transmitted to the type bars which pivot on an axis having theshape of a ring segment.

Moreover, the basket carrying the type bars effects a translatory motionwhen passing from small letters to capitals. Means must therefore beprovided so that, during this movement, the geometry of this kinematicchain is not altered. In order to avoid this disadvantage, mostmanufacturers employ an intermediate lever placed on the basket. Thislever also pivots on an axis in the shape of a ring segment and issituated in the same plane as the type bar. This solution isdisadvantageous because it tends to make the basket heavy and toincrease its bulk. This last point is not compatible with the minimumbulk conditions required for certain portable typewriters. Certainmanufacturers have by-passed this bulk ditficulty by various means butat the price of other disadvantages, such as bent key levers instead offlat levers, additional pivoting points for key levers i.e., three orfour levers instead of a single one.

Other manufacturers have provided, in the kinematic chain connecting thekey lever to the type bar, an intermediate lever pivoted on a movablerake which is moved by the movement of the motion lever. Since themovements of the basket and of the rake are not parallel, it isnecessary to provide a curved rake, on the one hand, and the twoconnecting joints of the draw-rod connecting the type bar and the leverpivoted on the rake cannot be chosen arbitrarily, on the other hand.

The mechanism according to the present invention is characterized inthat said rake is mounted so that the pivoting point of said leverpivoted on the rake moves on a line parallel to the direction ofdisplacement of the basket from a first to a second position and viceversa during the operation of the motion lever.

The accompanying drawing shows, diagrammatically and by way of example,one embodiment of the subject of the invention.

FIG. 1 is a side view, with partial sections, of this embodiment.

FIG. 2 is a partial view on a larger scale.

The mechanism shown includes type bars 1 pivoting at 2 in a movablebasket 3. This basket 3 is mounted on the base 4 by links 5, in orderthat it may move its axis from 2 to 2' as indicated in FIG. 2. Themovement is controlled by an eccentric 7, the pin 8 of which cooperateswith a fork 9 of the basket. The eccentric 7 is controlled from a motionor shift lever 10 by a kinematic chain including a draw-rod 11, a lever12 pivoted at 13, a drawrod 14 and a toothed segment 15 pivoted at 16.

The type bars 1 are controlled from key levers 17 pivoted at 18 by akinematic chain including a draw-bar 19, a lever 20 pivoted at 21 on amovable rake- 22 and a draw-rod 23. The rake 22, which pivots at 24, iscontrolled from the lever 12 by a link 25 pivoting at 26 on the rake 12and at 21 on the lever 22. Also provided are springs 27 for the returnof key levers 17.

As shown in FIG. 2 of the drawing, the kinematic striking chain isdisposed so that upon actuation of the motion lever 10, the pivot points21 of the levers 20 move on a line parallel to the direction ofdisplacement of the basket 3 as it moves from its first to its secondposition and vice versa. This arrangement permits use of a straight rake22 which is easier to manufacture than known rakes which are bent.

The operation of the mechanism is as follows:

When one presses on the key of the lever 10, its move ment istransmitted to the eccentric 7, thev pin 8 then driving the basket 3over a distance equal to the distance between the pins 2 and 2. Thepassage from position 2 to position 2', shown in dotted lines, of theaxis of the type bars corresponds to the passage from lower case type toupper case type. The members 11, 12, 14, 15 of the kinematic chain arethen in the positions 11, 12', 14 15', shown in dotted lines.

In order not to alter the geometry of the members of the kinematicstriking chain, the pivoting point 21 of the lever 20 is moved to 21' ina movement parallel to the direction of movement of the basket 3 and thepivots 22' and of the same distance. The members 19, 20, 23 of thekinematic striking chain then occupy the positions 19, 20', 23, shown indotted lines. Independently of the fact that the rake 22 is straight,another advantage of the parallel movement of the axes 2 and 21 residesin the fact that the attachment point of the draw-rod 23 to the lever 20may be chosen arbitrarily about the point 21 at the place which is themost convenient in order to obtain the best acceleration conditions ofthe type bar and of the touch of the keyboard.

I claim:

1. In a typewriter, a control mechanism for the type bars comprising abasket movable from a first position into a second position, type barspivoted on said basket, the pivots of said type bars being located on anarcuate line, control means including a shift lever for shifting saidbasket from a first position into a second position and vice versa, keylevers for actuating said type bars, a movable rake, levers pivoted onsaid rake, links connecting each key lever to its respective rake leverand connecting each rake lever to its respective type bar, said controlmeans comprising connecting means displacing said rake in relation tothe shifting of said basket from its first to its second position andvice versa by operation of said shift bar, said rake being mounted sothat the pivoting points of said levers pivoted on the rake are located,in the first and second position of said basket, on lines parallel tothe direction of the displacement of said basket from its first into itssecond position.

2. A control mechanism according to claim 1, wherein said rake isstraight, said levers carried by said rake being parallel to each otherand pivoted on a straight axis.

3. .A control mechanism according to claim 2, Wherein said rake ispivotally mounted on a part of the typewriter, and the connecting meansdisplacing said rake comprises 5 a link connected to said motion lever.

Hess 197-29 Helmond 197-74 Thyer 19774 X Nunderlich et al 19727 Yaeger19727 Ryan et a1 19717 ROBERT E. PULFREY, Primary Examiner.

E. S. BURR, Assistant Examiner.

1. IN A TYPEWRITER, A CONTROL MECHANISM FOR THE TYPE BARS COMPRISING ABASKET MOVABLE FROM A FIRST POSITION INTO A SECOND POSITION, TYPE BARSPIVOTED ON SAID BASKET, THE PIVOTS OF SAID TYPE BARS BEING LOCATED ON ANARCUATE LINE, CONTROL MEANS INCLUDING A SHIFT LEVER FOR SHIFTING SAIDBASKET FROM A FIRST POSITION INTO A SECOND POSITION AND VICE VERSA, KEYLEVERS FOR ACTUATING SAID TYPE BARS, A MOVABLE RAKE, LEVERS PIVOTED ONSAID RAKE, LINKS CONNECTING EACH KEY LEVER TO ITS RESPECTIVE RAKE LEVERAND CONNECTING EACH RAKE LEVER TO ITS RESPECTIVE TYPE BAR, SAID CONTROLMEANS COMPRISING CONNECTING MEANS DISPLACING SAID RAKE IN RELATION TOTHE SHIFTING OF SAID BASKET FROM ITS FIRST TO ITS SECOND POSITION ANDVICE VERSA BY OPERATION OF SAID SHIFT BAR, SAID RAKE BEING MOUNTED SOTHAT THE PIVOTING POINTS OF SAID LEVERS PIVOTED ON THE RAKE ARE LOCATED,IN THE FIRST AND SECOND POSITION OF SAID BASKET, ON LINE PARALLEL TO THEDIRECTION OF THE DISPLACEMENT OF SAID BASKET FROM ITS FIRST INTO ITSSECOND POSITION.